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UNITED STATES PATENT uhan v. noon, on NEWARK, nnwJnnsnY, Assume 'ro' 'rnrz-cnnnunoni MANUFACTURING con/[manor NEW YORK,

MANUFACTURE or SOLUBLE NlT'RO-QELLULOSE.

SPECIFICATION forming part of letters Patent fie. 806,519, dated October 14.1884.

An plldnt ionfilcd May 9. 1884. (No spccimenml v To all whom it may concernr Be itknown that I, FRANK V.-POL, a. citizen of the United States, and aresident of Newark, in thecouuty of Essex and State-of New Jersey, have invented certain new and useful Improvements in the Manufacture of Soluble Xitro- Cellulose,- of which the following is a specification.-

Theinvcution relates to the art of manufacro 'tnring what is known as soluble nitro-cellu-' lose," and it consists, especially, in a process whereby the spent acids are restored by the use of nitrates, and then employed as hereinafter 'dcscribed.. Y r

The novelty of theprocess consists in the use of nitrates for the purpose of restoring the spent acids in bulk and using the same continuously without'ehange, as hereinafter described. I I

The process of making soluble nitro-ccllulose as at present conducted in its most approved form consists-i n, first, nitrating the fiber by ineansof'a bath ot'inixcd acids; second,clarilying or filtering the spent acids which have been used to accomplishthe nitration of the fiber, and, third, restoring the strength of the clarified spentacids by theaddition of nitric and sulphuric acid. I

It has been found impracticable, in view of circumstances which need not here be recited, to' sorcgulatc the acidulous bath as t6 insure so; perfectly uniform .product. The character gotthe different batches of material;inevitably vary, frequently to such an extent as to inter rupt the regular course of manufacture.

.lo obviate this source of embarrassment and loss is one of the objects of the invention, which is accomplished, as hcrciubet'ore stated, by-thc use of nitrates to effect the restoration of the spent acids in bulk and their subsequent use according to methods well understood in the art.

In practice, take in ny given quaint-it y of spent acid, enough to supplyafactory for any given period. 'll'aviugr collected the same in an appropriatc vessel, an analysis is made whereby it is ascertained the quantity of nitric acid which is necessary to effect a restoration. Having arrived at a knowledge of the neces- 50 sary quantity, I add such quantity of a nitrate,

either metallic, earthy, or alkaline, as will accomplish the desired object. The nitrate, being'introduced, is decomposed bythe sulphuric acid present in the bath,whereby the .nii tric acid is liberated and the strength of the bath affected accordingly It is essential that great care be exercised in making an accurate analysis and in adding the precise quantity of the nitrate that may,

he demanded, as anydeficiency or excess in the quantity of nitrate supplied will resultin an improperly-nitrated compound and consequent failure in the production of the desired object.

Having in this way restored a large quantity of the spent acid to the condition in which itis desircdto use it, the same is employed continuously without variation, the spent acid resulting from the use of this lot being treated in the sameinauneras before, and thus a constant supply .of acid of the proper standard produced.

1n 'anotherapplieation filedby me on the 22d day of January, 1884, and bearing Serial No. 118,330, Ihave described and claimed a .process of restoring .spent acids .used in the manufacture of soluble nitrocellulose, the distinctive noveltyof which consists .in the use of a. nitrate the base of which forms, when introduced into the bath, an insoluble compound, whereby the bath is both restored and What I claim as my invention, auddesire to secure by Letters Elatent, is-

In the art of manufacturing soluble nitrocellulose, the process herein described of restoring the spent acids, which consists in restoring their strength in bull; by the introduction of a. suitable'quantity of a nitrate and employing the acidulous mixture thus restored continuously in the conversion of batches of material, substantially as described.

Signed at New York, in the county of New York and State of New York, this 8th day of May, A. 1). 18st.

' FRANK rooL.

Witnesses:

CHAS. C. GILL, I IIERMAN firm-nu" 

